consider the Hawaiian
green sea turtle as a
The most prominent turtle
researcher in the Islands,
whose work has chronicled
the severely depleted
population since the days in the
1970s when it was uncommon to find turtles
in nearshore waters, now says the population may be
recovered sufficiently to consider hunting them again.
This will be heresy to a generation of Hawai'i residents
raised to revere the turtle, who have accepted it as a
personal symbol, who have tattooed its image on ankle and
But Hawaiian turtle meat was once served in Hawai'i
restaurants. Enough residents—this writer included—are
old enough to have seen turtles caught and slaughtered on
the beaches. And to know that green sea turtle fat is green
in color, ostensibly dyed by the limu they eat.
During the last century, they have been hauled out of the
waters around the main Hawaiian islands, they've been
hauled off their nesting beaches—where they had no chance
of escape—and their eggs have even been harvested, dug up
out of the sand.
Turtles have not been legally harvested in more than 30
years, but they're now common again. They're seen gliding
through nearshore waters, grazing on beds of weed, their
big dark shells humping up on the ocean's surface, their
beaked heads poking up for air.
And far more turtles than are in nearshore waters are
still young and in a phase of their lives in which they
live out on the open sea.
George Balazs has spent a career monitoring the recovery
and the various difficulties of the turtles, and he has
taken the massive step of writing a paper that considers
the once-unthinkable possibility of allowing harvesting of
turtles once more.
With Australia ecological monitoring expert Milani Chaloupka,
Balazs in the journal Ecological Modelling, has written
“Using Bayesian state-space modelling to assess the recovery
and harvest potential of the Hawaiian green sea turtle stock.”
They studied the results of commercial fishing take of
turtles from 1944 to 1973, when fishing was halted. And
they looked at how many turtles showed up to nest from 1973
to 2004 at the turtles' primary nesting ground,the sandbars
of French Frigate Shoals in the Northwestern Hawaiian Islands.
The 1944 start date is important, because it was in that
decade that turtle take converted from subsistence to
Using statistical techniques, they worked out that the
turtle stock in 1974, when hunting was stopped, was about
20 percent of its level before hunting started. And after
30 years of protection, they figure it's now up to about
Although a successful one, it's a slow recovery, in part
because turtles are such long-lived and slow-to-mature
“So, this once-seriously depleted green turtle stock is
well on the way to recovery and a limited harvest might
now be demographically feasible,” the authors write.
Balazs and Chaloupka do not suggest all-out hunting can
be resumed. They suggest public discussion of “sustainable
harvest potential” and a public debate on “the restoration
of indigenous hunting rights in the Archipelago.”
Most of the turtles found in the main Hawaiian Islands are
still too small for harvest. And there's an issue that was
not apparently a problem in the harvesting days: many suffer
from grotesque external and internal tumors called
fibropapilloma. The cause of this disease, which affects
turtles worldwide, is not yet known. Does it make sense to
harvest for human consumption a diseased stock?
The Balazs-Chaloupka paper doesn't discuss that. It just
says that from a pure numbers standpoint, with a low enough
harvest quota, the population could be sustained.
The ensuing conversations will undoubtedly be animated.
© 2007 Jan W. TenBruggencate
Wednesday, August 29, 2007
Saturday, August 25, 2007
The most vulnerable place in Hawai'i for the arrival of new invasive species may be our harbors and waterways.
While air passengers' luggage and carryons are inspected and crew check for brown tree snakes in cargo containers, the bottoms of ships arrive daily covered with wildlife.
“We really have no protection against hull fouling, and travel through the freshwater lake (Lake Gatun) in the middle of the Panama Canal isn't sufficient to kill most barnacles. They just close up and wait, and the wait isn't that long for getting through Panama,” wrote Michael Hadfield, Professor of Zoology at the University of Hawaii at Manoa.
And a some of those animals may be “sleeper species,” getting comfortable in the Hawaiian environment before they make the genetic shifts required to become real pests.
Hadfield and co-author John Zardus review the issue of marine alien invasions in a couple of recent papers:“Multiple origins and incursions of the Atlantic barnacle Chthamalus proteus in the Pacific,” in Molecular Ecology in 2005; and “A tale of three seas: consistency of natural history traits in a Caribean-Atlantic barnacle introduced to Hawaii,” in Biological Invasions in 2006, with additional co-authors Chela Zabin, Fabio Bettini Pitombo and Vanessa Fread.
Using mitochondrial DNA, they tested Chthamalus in Hawai'i and found evidence that Hawai'i specimens are related to Atlantic representatives from several different areas. It shows that there were multiple immigrants that are now interbreeding.
The researchers also tested representatives of the barnacle in other south Pacific and western Pacific harbors, and found similar results.
“We found compelling evidence that it has arrived multiple times in the Pacific from several areas in its native range,” they wrote.
One of the odd things they found is that a significant proportion come from the coast of Brazil well south of Panama. It suggests that a fair number of the imports came around Cape Horn rather than through the Panama Canal. That may be because Chthamalus isn't as tolerant of the fresh water bath in Lake Gatun, and that some of the potential barnacle immigrants from that route died.
Although it's an invader, thus far there haven't been significant impacts from it, the authors say. But Hadfield said it seems to have the potential of some other weedy species: They simply hold on for a while, over time make an adaptation to their new environment, and then become problem species.
“In the case of introduced animals, its clear that a lot of predatory species have quickly undergone prey and even habitat shifts in new locales. Witness the predatory snail, Euglandina rosea, that came from relatively low, moist habitats in the U.S. Southeast where it ate a variety of other snails from soil litter or low trees. In Hawaii, it not only eats a variety of new prey (including all of our native tree snails), but also has ascended the mountains and ravines to live in habitats the likes of which don't occur in North and South Carolina, Georgia and Florida,” he said.
“Some people call these invaders 'sleeper species,' meaning that their introduction appears to be benign, until they finally 'adapt' and take off to become a major problem,” Hadfield said.
© 2007 Jan W. TenBruggencate
Friday, August 24, 2007
The coqui frog must be having a big impact on something it feeds on, because there seem to be a lot of them.
Beloved in Puerto Rico but driving people nuts in Hawai'i with its piercing nighttime calls, the coqui tree frog has invaded a number of habitats, and not a few back yards, in the Islands.
It has been vilified as a potential predator of native insects, although some folks suggest it might actually be a benefit, because it could reduce populations of invasive pest insects.
Which is it?
Maybe a problem for natives, but it doesn't seem to be much help with pest species, writes Utah State researcher Karen H. Beard in the May 2007 issue of Copeia, the quarterly journal of the American Society of Ichthyologists and Herpetologists. Beard studies the invasion of coqui frogs through their impacts on the environment, Her paper is entitled, “Diet of the invasive frog, Eleutherodactylus coqui, in Hawaii.”
To determine what impact the coqui might be having on insects, Beard went out to 11 sites on Maui and Hawai'i and collected hundreds of frogs, as well as collecting bugs and other creepy-crawlies from the same areas.
In comparing frog stomach contents with what she'd found in the environment, she concluded that the frogs are mostly feeding among the leaf litter.
They are also opportunistic, meaning their food sources change based on what's available.
But generally, they seem to do a pretty good job on ants, which aren't native to Hawai'i and which make up 30 percent of their food. Next most common are types of amphipods, relatives of shrimps and crabs, sometimes called landhoppers, which may or may not be native. The endangered Kaua'i cave amphipod, which lives in cracks and lava tube caves in the Koloa region of Kaua'i is in this group, so there are native animals in this group.
Beard's review found a higher proportion of the ants and amphipods in the frogs than in the environment, suggesting that the frogs key in on these species.
But they'll also eat mites, beetles, flies and other little critters
If anyone was hoping the frogs would be going after really annoying pests, like mosquitoes and termites, no such luck. Beard found no mosquitoes at all, and while termites were present, they represented less than one percent of the frogs' prey.
Beard concluded that endemic species—ones found in Hawai'i and nowhere else on the planet—may be at risk from the coqui, and that more research should be done in areas where endemic populations are high.
“It is these locations where E. coqui may have the greatest impact,” she wrote.
To learn more about the frogs, see www.hear.org/AlienSpeciesInHawaii/species/frogs/.
© 2007 Jan W. TenBruggencate
Wednesday, August 22, 2007
One of the important traits of some invasive plants is the ability to make their own fertilizer.
The firetree, Myrica faya, can do it. And as Peter Vitousek and Lawrence Walker, then both of Stanford University, reported in the journal Ecological Monographs back in 1989 (“Biological Invasion by Myrica Faya in Hawai'i: Plant Demoraphy, Nitrogen Fixation, Ecosystem Effects”), it quickly became a problem invader.
The firetree has the additional feature of producing a lot of fruit that birds like—so it has a built-in fast-spreading mechanism.
They found that the leaf litter of the firetree essentially fertilizes the ground.
“We concluded that biological invasion by Myrica faya alters ecosystem-level properties in this young volcanic area; at least in this case, the demography and physiology of one species controls characteristics of a whole ecosystem,” they wrote.
The problem, of course, is that one of the survival mechanisms of some native Hawaiian plants is the ability to survive in poor soils where other plant's can't. If aliens show up and begin scattering fertilizer in these habitats, they create further openings for a mass of other plants that otherwise couldn't compete with the natives.
The invasive two-spotted leafhopper, which attacks native and alien species alike but significantly damages firetree, may have reduced the plant's aggressiveness, although Vitousek in an email said that's more the case in dry areas than wet.
"Unfortunately, it looks green and vigorous across much of its range, despite the leafhopper, Vitousek wrote.
But there's another nitrogen-fixing invader following right on the fire tree's heels.
This time, it's the stately albizia, Falcataria moluccana, which has been fast-invading the back country on several islands in recent years. (It has also been known as Albizia falcata, Albizia falcataria, and Paraserianthes falcataria.)
“Invasion by N2-fixing tree alters function and structure in wet lowland forests of Hawai'i,” was printed in the October 2005 issue of “Ecological Applications,” R. Flint Hughes and Julie Denslow, of the U.S. Forest Service's Institute for Pacific Islands Forestry in Hilo, studied the trees in Kilauea lava flows 48 years old, 213 years old and 300 years old.
Like the firetree, the albizia fertilizes the ground around it. It spreads quickly due to seeds readily blown by the wind.
Among their findings was that native plants like 'ohi'a declined in the presence of the invaders, and other alien species, like strawberry guava increased in population.
“Results provide a clear example of how invasive tree species, by modifying the function and structure of the ecosystems that they invade, can facilitate invasion by additional nonnative species and eliminate dominant native species,” Hughes and Denslow wrote.
They added: “Invasive species pose major threats to the integrity and functioning of ecosystems. When such species alter ecosystem processes, they have the potential to change the environmental context in which other species survive and reproduce and may also facilitate the invasion of additional species.”
The nitrogen-fixing abilities of the albizia has been put to use in Hawai'i. Forester Bill Cowern on Kaua'i interplants albizia with valued hardwood species to reduce or eliminate the need to fertilize them. He has been experimenting with uses for the soft, fibrous wood of the species.
© 2007 Jan W. TenBruggencate
Tuesday, August 21, 2007
Feral cats have been spreading in the wild in Hawai'i, and new research indicates that all's not well with the environment, nor with the cats themselves.
The felines, some of which are just a generation or two out of domesticity, and others dating their heritage back to early European sailing ships, not only eat imported birds, like meijiro, cardinals, shama thrush and others, but they also attack native birds, often in the most remote terrain.
Wildlife scientists Steven Hess, Daniel Goltz, Raymond Danner, Kevin Brinck, Paul Banko, Heidi Hansen and others, working from the U.S. Geological Survey's Pacific Island Ecosystems Research Center at Kilauea, conducted a series of capture and test experiments on feral cats on Mauna Kea.
They've also been looking into cat issues in other ways. One is cameras set at bird nests.
Cats are opportunist feeders. A chick in a nest? They'll kill it, even if sometimes they don't eat it, Banko said. He estimated 10 percent of Mauna Kea's endangered palila chicks are taken each year by cats.
They also attack the Hawaiian state bird, the nene, sometimes eating mother geese as they sit on nests on the ground.
They will creep into seabird burrows, and take adults and chicks, which have no way out once the cats are in the entrance to the burrow.
A lot of the cats carry disease. Many have the cat form of HIV, feline immunodeficiency virus. Some also have the cat form of leukemia, feline leukemia virus.
And, as in most populations of cats, there is toxoplasmosis, a protozoan disease that doesn't make otherwise healthy cats ill, but can infect other animals. The last wild individuals of the critically endangered Hawaiian crow were pulled out of the wild into captivity when it was found that some were dying and others were ill from toxoplasmosis.
Cats pass toxoplasmosis through their feces, which grazing animals can inadvertently take up while feeding, and creatures like rats and pigs can get by feeding directly on cat scat. The disease can be passed to humans through the incompletely cooked meat of infected animals, or by directly contacting and ingesting infected cat droppings—for example by wiping your mouth after gardening in soil where a cat's done its business.
In humans, it's generally only a problem for the fetuses of women pregnant when they are infected, and in people with compromised immune systems. Toxoplasmosis can be treated if it's detected.
© 2007 Jan W. TenBruggencate
Sunday, August 19, 2007
Mosquitoes, the first of which arrived in Hawai'i in a sailing ship's water casks in 1826 at Lahaina, are among the more annoying things about living in the Islands.
Now there's hope that something can be done about mosquitoes—something besides fogging communities with pesticides. But more on that later.
All mosquitoes, as most folks know, are not created equal. Different species bite at different times, inhabit different territories, and carry different diseases.
That first mosquito, which arrived now more than 170 years ago was the southern house mosquito, Culex quinquefasciatus. It breeds in the smallest pools of water, including the crotches of plants, from sea level to more than a mile in elevation. Its main threat to the environment is that it carries avian pox and avian malaria. It is believed to be a key figure in the destruction of Hawaiian native birds—perhaps one of the world's most amazing examples of adaptive radiation. It will fly three miles to find a meal, and generally bites in the early evening.
The Yellow Fever mosquito, Aedes aegypti, which also carried dengue fever, showed up in 1892. It's a daytime biter.
In 1896, the Asian tiger mosquito, Aedes albopictus, showed up. It's sometimes called the forest day mosquito. It carries dengue fever. The tiger does fine with pockets of water in rocks and even buckets in your yard. It generally bites during the day, but doesn't fly far, so cleaning out old tires, tin cans and other sources of breeding water will help reduce numbers around the home. It is the most common of day-biting mosquitoes.
The inland floodwater mosquito, Aedes vexans nocturnus arrived in 1962. If you find a puddle in the yard or a water-filled tire depression along the road, look for it there. Good news: it hasn't been implicated in disease transmission. On the other hand, this is the one that bites at night, buzzing in your ear well into the pre-dawn hours.
The bromeliad or pineapple lily mosquito, Wyeomyia mitchellii, a 1981 arrival, appears to be limited to the few teaspoons of water that collect at the base of bromeliad leaves and in cut bamboo. Both this and the floodwater mosquito have not been known from Maui, but are on the other major islands. It is a very small mosquito, and will bite at dusk.
Another dengue-carrier, Aedes japonicus, showed up on the Big Island in 2004. It is a daytime biter, although it will continue harassing people into dusk.
Quarantine officials regularly catch new mosquito species. More than 40 have been stopped, apparently including the 2003 interception of the mosquito that transmits malaria in humans, Anopheles punctipennis.
Hawai'i's 2002 outbreak of dengue fever, with more than 100 confirmed cases, was linked to the Asian tiger mosquito, Aedes albopictus.
And several of the Hawai'i species can carry West Nile Virus.
For information on controlling mosquitoes around your home, see this state Department of Health site on the web: www.hawaii.gov/health/environmental/vector/mosquitoflyer.pdf.
The recommendations include using aerosol mosquito spray for adults, wearing insect repellent, and either using chemical means or things like mosquito fish to control the larvae in water bodies. Some research has been done , with some success, with using strains of the bacteria Bacillus thuringiensis on mosquitoes.
But to get to the teaser that started this story, Dutch researchers have found a fungus that attacks mosquitoes and can significantly shorten their lifespans.
Writing in the June 2007 edition of “Acta Tropica,” entomologists Ernst-Jan Scholte, Willem Takken and Bart Knols write of the “Infection of adult Aedes aegypti and Ae. albopictus mosquitoes with the entomopathogenic fungus Metarhizium anisopliae.”
(Entomopathogenic is a fancy word that means something that makes insects sick.)
They found that if the mosquitoes landed on a surface contaminated with the fungus, they became infected, and they lived 3 or 4 days, rather than the normal 17 to 18 days.
Would it also work on other mosquito species, and is there a way to use the fungus to control mosquitoes, without making other insects sick? That's still to be determined.
© 2007 Jan W. TenBruggencate
Saturday, August 18, 2007
We've long known that smoke is hazardous, but perhaps not in how many ways.
Wildfires blaze across the Hawaiian landscape during one of the state's most significant droughts, and research suggests that among the threats to humans are active fungal and bacterial spores.
Fires cause dramatic damage beyond just blackening the plants that burn.
Fires destroy the cover and promote subsequent erosion. They remove habitat for any number of bird, insect, mammal and other forms of life. They can so reduce populations of rare species that extinction looms.
And of course they threaten homes, agriculture, businesses, even lives.
But if you've ever coughed or had an allergic reaction in the presence of smoke, you might have wondered what was in there besides particles of soot.
More than we might have imagined, write researchers Sara and Forrest Mims, Texas researchers who conduct atmospheric studies and have worked at the Big Island's Mauna Loa Observatory. See www.forrestmims.org, for recent photographs, including one taken from Mauna Loa this year that Forrest Mimms says shows Asian dust visible in the atmosphere.
In a paper published in Atmospheric Environment, they review evidence that wildfires virtually always carry spores, and can carry them for thousands of miles. The paper is not new, having been published in 2004, but its message is topical in Hawai'i today.
Perhaps their most amazing finding: They were able to detect at Mauna Loa Observatory spores in smoke that originated from fires in Asia.
And the fires haven't necessarily sterilized the spores.
Mims and Mims found viable spores from both bacteria and fungi from smoke originating in the Yucatan, and they found spores from an Arizona fire.
They tried creating their own fires and testing the smoke. The result: grass, leaves, twigs and debris from a flood, when burned, all produced spores in the smoke.
Among the spores they've identified: Alternaria, which has been associated with hay fever and asthma; Cladosporium, which has been associated with respiratory disease; and Curvularia, which has been associated with infections of the eye.
Another good reason to stay out of the smoke, whether it's from a brush fire in your neighborhood or a campfire at the beach.
As a side note, the research on smoke also suggests that bacteria and fungi driven on the winds from Asia might have been some of the earliest inhabitants of the Hawaiian archipelago.
© 2007 Jan W. TenBruggencate
Hawai'i is paying increasing attention to alien pest invaders, but is it enough?
Consider the potential cost of one of them.
A team of researchers figures that the red imported fire ant, Solenopsis invicta, could cost the state $211 million a year if it showed up. This ant, known as RIFA for short, is the one that swarms and bites with a deeply painful venom.
It's costing billions of dollars elsewhere, has spread across the southern U.S., and “in 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawai'i,” wrote the authors of “Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii,” in the May 21 journal “Environmental Science and Policy.”
The writers are John Gutrich of Hawai'i Pacific University, Ellen VanGelder of the University of Hawai'i's Pacific Cooperative Studies Unit and Lloyd Loope of the USGS Pacific Island Ecosystems Research Center.
The state, with substantial federal help, is training dogs and keeping a lookout for brown tree snakes. The community is spending vast sums fighting alien species already here, like the hundreds of thousands of dollars spent to rid Lake Wilson of the aquatic weed Salivinia molesta. And some pests, like the two-spotted leafhopper, Sophonia rufofascia, are so widespread that the main hope is that some predator will show up or be specifically imported to keep them under some kind of control.
Gutrich and his team figure the RIFA will cause problems for homes, will drive cattle nuts, could affect the management of crops, will certainly affect recreation and so forth. They can start living in utility boxes, creating special problems for cable, phone and power companies. Dropping your beach blanket on a RIFA nest could cost you a trip to the hospital. (Imagine the impact on tourism.) Infants and kids are at special risk. Nationwide, 80 people are reported to have died from the stings.
Once established, the Hawai'i Ecosystems At Risk program says RIFA is virtually impossible to eradicate.
The researchers estimate $77 million a year in damages and costs of various kinds, and $134 million in lost recreational activities.
Their conclusion: The state would be advised to enact a program of “prevention, early detection and rapid response.”
For more information about the fire ant, see the Hawai'i Ecosystems at Risk web page, www.hear.org/AlienSpeciesInHawaii/species/solenopsis_invicta/.
Some folks will remind us that we already have fire ants, and that's true. We have three of them, but none is anywhere near as aggressive or toxic as RIFA.
© 2007 Jan W. TenBruggencate
Friday, August 17, 2007
Do Marine Life Conservation Areas work?
The answer, depending on what you mean by the question, appears to be yes, and no.
But the more appropriate response would appear to be, “Work at what?”
In the journal Ecological Applications in April, Oceanic Institute's Alan Friedlander, along with Eric Brown of the National Park Service at Kalaupapa and Mark Monaco of NOAA's National Centers for Coastal and Ocean Science, wrote of “Coupling ecology and GIS to evaluate efficacy of marine protected areas in Hawaii.”
It's a scary title, but a couple of bits of interesting information hide in there.
They studied the state's 11 Marine Life Conservation Areas.
One finding: There are indeed more and bigger fish generally inside than outside the areas. There are also more predatory fish inside. That's interesting in part because recent research has shown that unfished, intact marine ecosystems, like those in the Northwestern Hawaiian Islands and at Palmyra Atoll in the Line Islands, have dramatically higher percentages of predatory fishes than heavily fished areas like the main Hawaiian Islands.
Another finding: They also found that there's not a lot of spillover into the fished areas next to the conservation areas. They assume that could be because the conservation areas are really too small to have an appreciable impact on fish populations nearby.
“Overall fish biomass was 2.6 times greater in the MLCDs compared to open areas. In addition, apex predators and other species were more abundant and larger in the MLCDs, illustrating the effectiveness of these closures in conserving fish populations within their boundaries,” the authors wrote.
A further finding of interest: The bigger the preservation area, the more and bigger the fish seem to be. Here's how they phrased that:
“Although size of these protected areas was positively correlated with a number of fish assemblage characteristics, all appear too small to have any measurable influence on the adjacent fished areas. These protected areas were not designed for biodiversity conservation or fisheries enhancement yet still provide varying degrees of protection for fish populations within their boundaries.”
The message from this, perhaps, is that a marine preserve, regardless of size, will have benefits in terms of more wildlife. But if it's too small, don't expect it to enhance fishing success in neighboring areas.
There IS some evidence that marine preserves, if properly designed, can improve overall catch.
In Kona, a collection of reserves, designated fish replenishment areas, was established to protect aquarium fish from overcollecting.
Thirty-five percent of the West Hawai'i coastline was closed to marine fish aquarium collecting, in a series of nine closed areas running from North Kohala all the way down to Miloli'i.
After just a few years, the fish populations recovered. But importantly, the catches of aquarium fish in the neighboring areas improved, and it turned out that the overall aquarium fish catch from all of West Hawai'i increased.
© 2007 Jan W. TenBruggencate